Signal Clipping for Power Amplifier EVM Optimization
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Solution Overview
Problem
Conventional signal clipping methods, such as Peak Cancellation Crest Factor Reduction (PC-CFR), increase error vector magnitude (EVM) uniformly across different modulation schemes, leading to inefficient power amplifier performance due to a constant cancellation pulse approach that does not meet varying EVM requirements.
Innovation Solution
A method that performs peak detection and generates a cancellation pulse sequence based on scheduling information indicating the modulation scheme used for each resource block, adjusting the amplitude and phase of cancellation pulses to meet specific EVM requirements for different modulation schemes, thereby optimizing power amplifier efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional peak cancellation CFR algorithm is used to decrease peak-to-average ratio, then power amplifier efficiency is improved, but error vector magnitude increases uniformly across all modulation schemes
Solution Approach 1:
The patent applies local quality by assigning different cancellation pulse sequences with different amplitudes to different modulation schemes. Specifically, the first cancellation pulse sequence with a first amplitude is assigned to a first modulation scheme, while a second cancellation pulse sequence with a second amplitude is assigned to a second modulation scheme. This allows the clipping noise cancellation to be optimized locally for each modulation scheme's specific EVM requirements, rather than applying a uniform cancellation approach that degrades all schemes equally.
2Device complexity
If a constant cancellation pulse is used for all resource blocks, then device complexity is reduced, but adaptability to different modulation schemes deteriorates
Solution Approach 1:
The patent implements parameter changes by dynamically adjusting the amplitude parameter of cancellation pulse sequences based on the modulation scheme being used. The network device determines the modulation scheme for each resource block and selects appropriate cancellation pulse sequences with amplitudes tailored to that scheme's characteristics. This allows the system to adapt to different modulation schemes without requiring completely different cancellation mechanisms, balancing complexity and adaptability.
Data Source
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AI summary
The present invention discloses a signal clipping processing method and a device, so as to meet EVM requirements of different modulation schemes, thereby improving efficiency of a power amplifier. The method includes: performing peak detection on an input signal, so as to obtain amplitude information, phase information, and location information of a peak signal of the input signal; obtaining, according to amplitude information and phase information of each peak signal, a peak forming factor corresponding to each peak signal, and separately outputting, according to location information of each peak signal, a corresponding cancellation pulse sequence, where the cancellation pulse sequence is determined according to scheduling information of a BBU, and the scheduling information is used to indicate a modulation scheme used when each resource block for transmitting the input signal is used to transmit a data symbol; and calculating a sum of products of peak forming factors corresponding to all peak signals and cancellation pulse sequences corresponding to all the peak signals, so as to obtain a clipping noise, and using a difference between the input signal and the clipping noise as a signal obtained after clipping processing.